Course Content
Ultimate HTML
Every punctuation mark, attribute, and tag - whether it's the tag name, opening and closing, or a bracket - is crucial in code. However, for beginners, it can be difficult to keep track of all of them. Fortunately, validators are available to help.
Validation aims to identify syntax errors in the markup of an HTML document and inconsistencies between the document and the HTML specification specified in <!DOCTYPE >
. Validators are software programs that can perform these checks. After validation, your document either passes, or you will receive a list of suggested revisions to make.
Note
Validators do not check semantics. They check HTML syntax and adhering to the specified standards
Let's consider the next source https://validator.w3.org/nu/
. To check the HTML code you need only two steps: provide the code and click check button. The validator can checks the next items:
- Tag spelling correctness
- Attributes using correctness
- Tag opening/closing correctness
- Tag nesting correctness
Let's consider such code with mistakes.
index.html
index.css
index.js
We get the next messages:

Errors must be fixed in the order they are listed. Warnings are optional to correct, but analyzing them and ensuring the markup is high quality is good practice.
Let's fix all the errors.
index.html
index.css
index.js
Validator can ...
Select a few correct answers
Section 2.
Chapter 6